☆artificial

　　synthetic, fabricated, contrived, fake, mock, bogus, counterfeit, pseudo

　　☆conventional

　　traditional, historical, past; accepted, common, regular, routine, mainstream, ordinary

　　☆demand

　　request, claim, need, order, require, call for

　　☆decline

　　decrease, degeneration, drop, fall, recession, depression, reduction, slump, worsening

　　☆develop

　　evolve, advance, grow, improve, progress, flourish

　　☆difficulty

　　handicap, hardship, adversity, challenge, complication, dilemma, perplexity, plight, trouble

　　☆early

　　first, old, ancient, primitive, previous, former, remote

　　☆find

　　discover, come across, encounter, hit on, expose, notice, note, observe, recognize, spot, uncover

　　☆future

　　what's next, prospect, approaching, expected, destined, forthcoming

　　☆how

　　describe, operate, explain, clarify, demonstrate, eludicate, expound, illustrate, interpret, account for

　　☆inevitable

　　unavoidable, certain, destined, fated, inescapable, sure

　　☆militant

　　armed, belligerent, army, weapon, warlike

　　☆objection

　　commercial challenge, complaint, disapproval, opposition, protest, query, question, remonstration

　　☆obstacle

　　bar, barricade, barrier, block, blockage, check, obstruction, problem, snag, hurdle

　　☆prevalent

　　common, usual, prevailing, widespread, systematic, collective, general, popular

　　☆reduce

　　curtail, cut, decrease, halve, impair, lessen, moderate, trim, slash